msm: mdss: Configure TE GPIO using gpiomux framework

The TE GPIO needed on command mode panels has a gpio_func
value of 1. Acquiring resources of this gpio using gpio_request
API might configure this to a common gpio which has
gpio_func value equal to 0. Hence control this gpio using
the gpiomux framework.

Change-Id: I2e14ada484a6d20774030393ae6549f05ac1e8db
Signed-off-by: Padmanabhan Komanduru <pkomandu@codeaurora.org>